1. Field of the Invention
The present invention relates to an ultrasonic probe for microscopic operations that is used under microscopic observation.
2. Description of the Related Art
In recent years, a surgery system composed of an observation/imaging apparatus and a surgical apparatus that are combined based on a region to be operated or a surgical procedure has been used in the field of medicine.
The observation/imaging apparatus includes an endoscope, a laparoscope (optical instrument), and a surgical microscope. The endoscope has a soft insertion unit inserted into a body cavity through the oral cavity or anus. The laparoscope (optical instrument) has a rigid insertion unit indwelled in the abdominal cavity using a trocar for piercing the wall of the abdominal cavity. The surgical microscope enables observation of fine nerves or vessels under magnification.
An example of medical systems is a microscopic surgery system that is a type of medical system for enabling observation of fine nerves or vessels under magnification and helping perform surgery under microscopic observation. The microscopic surgery system is employed in the field of neurosurgery. In the microscopic surgery system, a handpiece or the like is manipulated for treatment while a region concerned is observed under magnification through an eyepiece unit of a surgical microscope.
For example, when the microscopic surgery system is used to perform cerebral surgery, the surgery is performed under optical observation. It is therefore impossible to observe a deeper part of a region than an observed surface thereof during the surgery. For this reason, magnetic resonance imaging (hereinafter MRI) or computed tomography (hereinafter CT) is performed in order to produce tomographic images of the region to be treated prior to surgery.
However, even when the tomographic images depicting the region to be treated and its surroundings are produced in advance, a disadvantage of a brain shift occurs due to craniotomy. The brain shift is a phenomenon that the actual position of the brain having undergone craniotomy is different from the position thereof detected in a diagnostic image produced through CT or MRI before surgery. Moreover, some surgeons want to check a deeper part of a region than the observed surface thereof during surgery. Therefore, a ultrasonic probe for cerebral surgery or craniotomy (hereinafter, a cerebral surgery probe) or a catheter type ultrasonic probe that has a small diameter and can radiate high-frequency ultrasonic waves and offer a high resolution and high image quality is often used in combination with a surgery system during surgery.
However, when the cerebral surgery probe is used under microscopic observation, the distal part of the probe is so large in diameter that it blocks a field of view given by a microscope. For preventing the cerebral surgery probe from blocking the field of view, the cerebral surgery probe is located away from a lesion in a region to be observed, and the lesion is scanned ultrasonically. At this time, since a far point is observed, the frequency of ultrasonic waves is set to a lower value. This leads to disadvantages of a lower resolution and degraded image quality.
On the other hand, assume that the catheter type ultrasonic probe is located near a lesion under microscopic observation in order to produce high-quality images for the purpose of observation of the lesion. Since the ultrasonic probe is so soft that its maneuverability is poor, it is hard to locate the ultrasonic probe at a predetermined position under microscopic observation for the purpose of producing a desired view image.
Moreover, the ultrasonic probe that is a device employed in surgery must be sterilized prior to use. The ultrasonic probe must therefore be disposable or must be able to be autoclaved, or anyhow, sterilized.